Imaging apparatus with scene analysis

ABSTRACT

An imaging apparatus comprises an image-capturing element that outputs image signals representing a plurality of color components and an analyzing device that analyzes a captured photographic image based upon image signals with linearity, which are output from the image-capturing element.

INCORPORATION BY REFERENCE

The disclosure of the following priority application is hereinincorporated by reference:

-   Japanese Patent Application No. 2006-105364 filed Apr. 6, 2006

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an imaging apparatus that executesscene analysis by using image data output from an image-capturingelement.

2. Description of Related Art

Japanese Laid Open Patent Publication No. 2001-103508 discloses a camerathat executes image processing on raw data provided by animage-capturing element and then executes scene analysis based upon aphotographic image generated through image processing.

SUMMARY OF THE INVENTION

However, there is a problem in that a significant length of time isrequired to execute analysis processing for purposes of scene analysisby generating an image from raw data, an optimal solution to which isyet to be proposed.

An imaging apparatus according to the present invention comprises animage-capturing element that outputs image signals representing aplurality of color components and an analyzing device that analyzes acaptured photographic image based upon image signals with linearity,which are output from the image-capturing element. It is preferred thatthe image signal with linearity is RAW data.

The analyzing device of the imaging apparatus may analyze thephotographic image based upon a discrete spectral distribution of theplurality of color components represented in the image signals. Theanalyzing device of this imaging apparatus may analyze the photographicimage based upon spectral characteristics manifesting in small areasdefined by dividing an entire area of the photographic image and anabsolute brightness value calculated in correspondence to each of thesmall areas as well as spectral characteristics manifesting over theentire area.

The analyzing device of the imaging apparatus may analyze a light sourceby calculating color continuity manifesting over an entire area of thephotographic image based upon discrete spectral characteristics of theplurality of color components represented in the image signals.

It is preferable that the analyzing device of the imaging apparatusextracts an achromatic area within the photographic image based uponcontinuity of spectral characteristics manifesting over an entire areaof the photographic image and continuity of the spectral characteristicsmanifesting in small areas defined by dividing the entire area. Theanalyzing device of the imaging apparatus may extract a small area as anachromatic area if the shape of a curve representing the spectralcharacteristics manifesting over the entire area substantially matchesthe shape of a curve representing the spectral characteristicsmanifesting in the small area.

The analyzing device of the imaging apparatus may extract a feature ofthe photographic image based upon discrete spectral characteristics ofthe individual color components manifesting over an entire area of thephotographic image and discrete spectral characteristics of theindividual color components manifesting in small areas defined bydividing the entire area. In this case, the imaging apparatus extractsthe feature by identifying a color inherent to a subject.

The analyzing device of the imaging apparatus can calculate an absolutebrightness value for an entire area of the photographic image based uponbrightness values corresponding to the individual color componentsdetected over the entire area and estimate a photographing locationbased upon the absolute brightness value. The analyzing device of theimaging apparatus may calculate a color temperature for the entire areaof the photographic image and estimates a photographing condition basedupon the color temperature and the absolute brightness value.

It is preferable that the imaging apparatus further comprises anarithmetic operation circuit that determines through arithmeticoperation photographing condition settings, at which a photographingoperation is to be executed by the image-capturing element, based uponanalysis results provided by the analyzing device. In this case, theimaging apparatus may further comprise a selection unit that selects aspecific photographing mode among a single shot mode, a continuousshooting mode, a dynamic image mode and a through image mode and thelike. The arithmetic operation circuit of this imaging apparatusdetermines through arithmetic operation the photographing conditionsettings based upon the analysis results and results of the selectionmade by the selection unit.

It is preferable that the imaging apparatus further comprises an imageprocessing circuit that executes image processing on the image signalsbased upon analysis results provided by the analyzing device. In thiscase, the imaging apparatus may further comprise a selection unit thatselects a specific photographing mode among a single shot mode, acontinuous shooting mode, a dynamic image mode, a through image mode andthe like. The image processing circuit of this imaging apparatusexecutes the image processing based upon the analysis results and theresults of the selection made by the selection unit.

The image-capturing element of the imaging apparatus may be aphotographic image-capturing element that outputs photographic imagesignals representing a plurality of color components by capturing asubject image passing through a photographic lens.

The imaging apparatus may further include, in addition to theimage-capturing element, a photographic image-capturing element thatoutputs photographic image signals representing a plurality of colorcomponents by capturing a subject image passing through a photographiclens. The image-capturing element and the photographic image-capturingelement of the imaging apparatus may be respectively a firstimage-capturing element that has first spectral characteristics withregard to the plurality of color components and a second image-capturingelement that has second spectral characteristics different from thefirst spectral characteristics with regard to the plurality of colorcomponents. The analyzing device of the imaging apparatus analyzes aphotographed image based upon image signals with linearity, which areoutput from the first and second image-capturing elements. The firstimage-capturing element of the imaging apparatus may be an auxiliaryimage-capturing element that is disposed at a position equivalent to theposition of the photographic image-capturing element relative to thephotographic lens and outputs auxiliary image signals. In this case, thenumber of pixels at the auxiliary image-capturing element of the imagingapparatus is smaller than the number of pixels at the photographicimage-capturing element.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the essential structure adopted in the single lens reflexelectronic camera achieved in an embodiment of the present invention;

FIG. 2 is a block diagram showing the circuit structure adopted in thesingle lens reflex electronic camera achieved in the first embodiment ofthe present invention;

FIG. 3 presents an example of spectral distribution manifested by rawdata over the photographic image, with FIG. 3A showing the spectrum ofthe raw data, FIG. 3B showing continuity in the spectral distributionestimated based upon the data in FIG. 3A and FIG. 3C showing an exampleof the correlation that may exist between a spectral distribution curveand the light source;

FIG. 4 illustrates an example of color information detection fordetecting color information with regard to a primary subject based uponthe spectral distributions manifesting in individual block areas, withFIG. 4A showing how the entire area of the photographic image may bedivided into a predetermined number of block areas and FIG. 4B showingthe spectral distribution that may manifest in block areas r1 throughrn:

FIG. 5 presents examples of tables that may be used when extracting thefeature of the subject, with FIG. 5A showing Table 1, which indicatesthe correspondence among the R, G and B value ratios over the entireimage plane, the color temperature and the coefficient and FIG. 5Bshowing Table 2, which indicates the correspondence between the R, G andB value ratios and the color temperature in the block areas;

FIG. 6 presents examples of spectral distribution curves that maymanifest in correspondence to the entire area of the photographic imageand a block area when the block area is judged to be an achromatic area;

FIG. 7 presents a flowchart of the overall operation executed in thesingle lens reflex electronic camera achieved in the embodiment;

FIG. 8 presents a flowchart of the operation executed in a single shotmode in the first embodiment;

FIG. 9 presents a flowchart of the operation executed in a continuousshooting mode in the first embodiment;

FIG. 10 presents a flowchart of the operation executed in a dynamicimage mode in the first embodiment;

FIG. 11 presents a flowchart of the operation executed in a throughimage display mode in the first embodiment;

FIG. 12 presents a flowchart of the scene analysis processing operationexecuted in the embodiment;

FIG. 13 is a block diagram of the circuit structure adopted in thesingle lens reflex electronic camera achieved in a second embodiment ofthe present invention;

FIG. 14 presents a flowchart of the operation executed in the singleshot mode in the second embodiment;

FIG. 15 presents a flowchart of the operation executed in the continuousshooting mode in the second embodiment;

FIG. 16 presents a flowchart of the operation executed in the dynamicimage mode in the second embodiment;

FIG. 17 presents a flowchart of the operation executed in the throughimage display mode in the second embodiment;

FIG. 18 is a block diagram of the circuit structure adopted in thesingle lens reflex electronic camera achieved in a third embodiment ofthe present invention;

FIG. 19 presents a flowchart of the operation executed in the singleshot mode in the third embodiment;

FIG. 20 presents a flowchart of the operation executed in the continuousshooting mode in the third embodiment;

FIG. 21 presents a flowchart of the operation executed in the dynamicimage mode in the third embodiment;

FIG. 22 presents a flowchart of the operation executed in the throughimage display mode in the third embodiment;

FIG. 23 illustrates spectral distributions that may be achieved byaltering the spectral sensitivity characteristics of the photographicimage-capturing element and the auxiliary image-capturing element, withFIG. 23A showing the case in which a spectral sensitivity width incorrespondence to the R, G and B colors of the auxiliary image-capturingelement 19 is different from that of the photographic image-capturingelement 13 and FIG. 23B showing the case in which the spectralsensitivity peaks of the R, G and B colors of the auxiliaryimage-capturing element 19 is different from those of the photographicimage-capturing element 13; and

FIG. 24 presents a diagram summarizing the correspondence between theimage-capturing element used for the scene analysis and the processingexecuted in each of the embodiments.

DESCRIPTION OF PREFERRED EMBODIMENT First Embodiment

The following is an explanation of an embodiment of the presentinvention, given in reference to the drawings. FIG. 1 shows theessential structure adopted in the single lens reflex electronic cameraachieved in the first embodiment of the present invention. A detachableviewfinder device 20 and an exchangeable lens 24 are both mounted at acamera body 10 in FIG. 1.

Subject light having passed through the exchangeable lens 24 and enteredthe camera body 10 is guided upward via a quick-return mirror 11, whichis positioned as indicated by the dotted line prior to a shutterrelease, to form an image at a viewfinder mat 14. The subject light thenenters a pentaprism 15. The pentaprism 15 guides the subject lighthaving entered therein toward an eyepiece lens 16 and also guides partof the subject light to a prism 17. The light having entered the prism17 then enters an auxiliary image-capturing element 19 via a lens 18 andforms a subject image on the imaging surface of the auxiliaryimage-capturing element. The auxiliary image-capturing element 19 isdisposed at a position that is optically equivalent to the position of aphotographic image-capturing element 13 relative to the exchangeablelens 24. The auxiliary image-capturing element 19, which may beconstituted with a CCD image sensor equipped with a plurality ofphotoelectric conversion elements each corresponding to a pixel,captures the subject image formed on its imaging surface and outputsphotoelectric conversion signals corresponding to the brightness of thesubject image. In the first embodiment, a brightness value of thesubject is calculated based upon the output signals provided from theauxiliary image-capturing element 19. In other words, the auxiliaryimage-capturing element 19 is utilized for exposure calculation.

Following a shutter release, the quick-return mirror 11 rotates to theposition indicated by the solid line, the subject light is guided to thephotographic image-capturing element 13 via a shutter 12 and a subjectimage is formed on the imaging surface of the photographicimage-capturing element. The photographic image-capturing element 13,which may be constituted with a CCD image sensor equipped with aplurality of photoelectric conversion elements each corresponding to apixel, captures the subject image formed on the imaging surface andoutputs a photoelectric conversion signals corresponding to thebrightness of the subject image.

The number of pixels at the photographic image-capturing element 13 isgreater than the number of pixels at the auxiliary image-capturingelement 19. The photographic image-capturing element 13 may be equippedwith, for instance, at least several million pixels, whereas theauxiliary image-capturing element 19 may be equipped with, for instance,several hundred thousand pixels. At the imaging surface of each of thephotographic image-capturing element 13 and the auxiliaryimage-capturing element 19, R (red), G (green) and B (blue) colorfilters are disposed each in correspondence to the position of aspecific pixel. Since each image-capturing element captures a subjectimage through the color filters, imaging signals output from theimage-capturing element each contain color information expressed in anRGB colorimetric system.

FIG. 2 is a block diagram showing the circuit structure adopted in theelectronic camera achieved in the first embodiment. In the electroniccamera in the first embodiment, scene analysis is executed by usingimage data (raw data) output from the photographic image-capturingelement 13. It is to be noted that since the output signals from theauxiliary image-capturing element 19 are utilized for the exposurecalculation but not for the scene analysis in the first embodiment, FIG.2 does not show the auxiliary image-capturing element.

A timing generator (TG) 32 generates a timing signal in response to acommand output from a main CPU 31 and provides the timing signal to adriver 33, an AFE (analog front end) circuit 34 and an A/D conversioncircuit 35. The driver 33 generates a drive signal to be used to engagethe photographic image-capturing element 13 in electrical charge storageand then in transfer of the stored electrical charges, by using thetiming signal and provides the drive signal thus generated to thephotographic image-capturing element 13. The AFE circuit 34 executesanalog processing (such as gain control) on photoelectric conversionsignals (stored electrical charges) output from the photographicimage-capturing element 13. The A/D conversion circuit 35 converts theimaging signals having undergone the analog processing to digitalsignals. The raw data constituted with these digital signals are outputto an image processing circuit 30 and a sub CPU 53. As detailed later,the sub CPU 53 executes scene analysis by using the raw data.

The image processing circuit 30 and the sub CPU 53 are connected to themain CPU 31. The main CPU 31 executes a specific arithmetic operation byusing signals input thereto from various blocks including the imageprocessing circuit and the sub CPU 53 and outputs control signalsgenerated based upon the arithmetic operation results to the individualblocks. The image processing circuit 30, which may be, for instance, anASIC, executes image processing on the digital image signals inputthereto from the A/D conversion circuit based upon scene analysisresults input thereto from the sub CPU 53 via the main CPU 31. The imageprocessing executed by the image processing circuit 30 includes imagepreprocessing and image post processing.

In the image preprocessing, outline emphasis, color temperatureadjustment (white balance adjustment) and the like are executed on theimage (raw digital image signal) captured by the photographingimage-capturing element 13. The image preprocessing is executed basedupon the analysis results obtained through scene analysis processing tobe detailed later. In the image post processing, format conversion isexecuted for the digital image signals having undergone the imagepreprocessing. Through the format conversion, the digital image signalsare converted to a format optimal for image compression.

The sub CPU 53 executes the scene analysis to be detailed later by usingthe digital image signals (raw data) input thereto from the A/Dconversion circuit 35. The sub CPU 53 outputs information indicating thelight source (color temperature), the photographing location, the colorof the primary photographic subject, the characteristics of the primaryphotographic subject and the like, which is obtained by executing thescene analysis, to the image processing circuit 30 via the main CPU 31.The scene analysis results are used in image processing executed in asingle shot mode, a continuous shooting mode, a dynamic image mode and athrough image display mode. In addition, in the continuous shootingmode, the dynamic image mode and the through image display mode, thescene analysis results are also used to determine photographingcondition settings such as the exposure value for an image to bephotographed subsequently.

An image compression circuit 44 executes image compression processing onthe digital image signals having undergone the image postprocessing atthe image processing circuit 30 by adopting a specific method such asthe JPEG method. A display image generation circuit 42 generates displaydata to be used to display the captured image at an external monitor 43by using the digital image signals having undergone the imagepreprocessing. At the external monitor 43, which may be constituted withan LCD, the image reproduced by using the display data is displayed.

A buffer memory 41 is used to temporarily store data currentlyundergoing the image preprocessing, the image postprocessing, the imagecompression processing and the display data generation processing anddata having undergone such processing. It is also used to temporarilystore image signals corresponding to a plurality of frames of imagescaptured in succession in the continuous shooting mode and the dynamicimage mode. In a recording medium 45 constituted with a memory card orthe like that can be detachably loaded into the electronic camera body10, the image data resulting from the image compression processing arerecorded.

A halfway press switch 47 and a full press switch 48, which are turnedon/off by interlocking with a depression of a shutter release button(not shown), each output an ON signal or an OFF signal to the main CPU31.

Via a mode selector switch 52, the electronic camera operation can beswitched to a photographing mode, the through image display mode, areproduction or playback mode or the like. The continuous shooting mode,the single shot mode, the dynamic image mode or the like can be selectedas the photographing mode. In the continuous shooting mode, images arephotographed by driving the quick-return mirror 11 up/down for eachphotographic frame if the continuous shooting speed is set at a levellower than a predetermined continuous shooting speed, but images arephotographed by holding the quick-return mirror 11 at the UP positionindicated by the solid line in FIG. 1 if the continuous shooting speedsetting is equal to or higher than the predetermined continuous shootingspeed. In the through image display mode, images are displayed at theexternal monitor 43 as dynamic images without executing photographingprocessing or recording processing. By performing a specific operation,the photographer is able to choose to drive the quick-return mirror 11up/down in correspondence to each frame or to hold the quick-returnmirror at the UP position indicated by the solid line in FIG. 1 in thethrough image display mode. In the reproduction mode, image datarecorded in the recording medium 45 are read out and an image reproducedby using the image data is displayed at the external monitor 43.

A focal point detection device 49 detects a focal point adjustment stateachieved with the lens 25 in response to a command output from the mainCPU 31 and outputs a detection signal to the main CPU 31. A lens drivedevice 50 drives the lens 25 forward/backward along the optical axis inresponse to a command issued by the main CPU 31. A lens informationinput unit 51 detects lens information indicating the aperture value andthe like at the exchangeable lens 24 and outputs a detection signal tothe main CPU 31.

As the photographer performs a photographing location time zoneselection operation based upon a map displayed at the external monitor43, an internal clock at a photographing location setting unit 60 isadjusted to the local time at the photographing location and thephotographing location setting unit 60 then outputs a time point signalto the main CPU 31. Alternatively, the photographing location settingunit 60 may set the latitude, the longitude and the altitude of thephotographing location, UTC (coordinated universal time) data or thelike based upon information received from a GPS (global positioningsystem).

—Scene Analysis Based Upon Raw Data—

The following is a detailed explanation of the scene analysis executedby the sub CPU 53.

The sub CPU 53 includes as its functional blocks a processing unit 54and a scene analysis unit 55. The processing unit 54 processes raw datainput thereto from the A/D conversion circuit 35, which are constitutedwith image signals having linearity. Based upon the light intensitydistribution of imaging signals output through the color filters eachcorresponding to the R color, the G color or the B color at thephotographic image-capturing element 13, the processing unit 54 detectsthe spectral distribution manifesting over the entire area of thephotographic image and outputs the detected spectral distribution to thescene analysis unit 55. In addition, the processing unit 54 divides thepixels at the photographic image-capturing element 13 into blocks eachcorresponding to a specific area, so as to allow the image signals to behandled in units of individual block areas. The processing unit 54 isthus able to detect the spectral distribution in each block area and anabsolute brightness value corresponding to each block area and to outputthe detection results to the scene analysis unit 55.

The scene analysis unit 55 executes scene analysis based upon thespectral distribution and the absolute brightness value corresponding toeach block area, as well as the spectral distribution manifesting overthe entire area of the photographic image, which are all input from theprocessing unit 54, and photographing information indicating thephotographing distance, the focal length, the photographing time, thephotographing location and the like, which is input from the main CPU31, by referencing various tables stored in a database 56. The sceneanalysis unit 55 executes scene analysis by detecting light sourceinformation (color temperature), identifying the photographing location,detecting color information pertaining to the primary photographicsubject and extracting feature of the primary photographic subject. Theresults of the scene analysis are output to the main CPU 31.

—Color Temperature—

Based upon the spectral distribution over the entire area of thephotographic image detected by the processing unit 54, the sceneanalysis unit 55 detects the light source information (colortemperature). The R, G and B outputs obtained as the raw data indicate adiscrete spectral distribution as in the spectrum presented in FIG. 3A.Based upon these discrete data, the scene analysis unit 55 estimatescontinuity of the spectral distribution as indicated by the bold line inFIG. 3B and detects the light source in correspondence to the shape ofthe continuous curve. FIG. 3C presents an example of the correspondencebetween the spectral distribution curve and a specific light source. Thesolid line indicates the spectral distribution curve achieved by usingan incandescent lamp with a color temperature at approximately 2850° K,the spectral distribution curve achieved by using daylight with a colortemperature of approximately 6500° K as the light source is indicated bythe dotted line and the spectral distribution curve achieved by using atypical light mix as the light source is indicated by the one-pointchain line. It is to be noted that information indicating such acorrespondence is stored in advance at the database 56 in a table formator the like and is read out by the scene analysis unit 55 when it isengaged in light source information detection.

—Identifying the Photographing Location—

Based upon the absolute brightness values detected by the processingunit 54, the scene analysis unit 55 estimates the photographinglocation. The absolute brightness value corresponding to each block areais calculated by the processing unit 54 as expressed in (1) below byusing the R, G and B outputs in the raw data.Y=0.3R+0.59G+0.11B  (1)

Based upon the absolute brightness values calculated as expressed in (1)above, the scene analysis unit 55 makes a decision with regard to thephotographing location, i.e., as to whether or not the image has beenphotographed indoors or outdoors. For instance, if the absolutebrightness values are equal to or greater than a predetermined thresholdvalue, the photographing location is judged to be an outdoors location.In addition, the scene analysis unit 55 further determines specificconditions at the photographing location by using the light sourceinformation explained earlier. Namely, based upon the absolutebrightness values and the color temperature, the scene analysis unit 55is able to determine that the photographing location was an indoorslocation illuminated by a fluorescent lamp, that the photographinglocation was an indoors location illuminated by an incandescent lamp orthe like. For instance, the relationship among the absolute brightnessvalue, the color temperature and the light source is stored in a tableformat or the like at the database 56 and the scene analysis unit 55makes a decision with regard to the photographing location byreferencing this table. Furthermore, the scene analysis unit 55 is ableto identify a specific photographing locale, e.g., Hawaiian seaside orHong Kong at night, based upon information indicating the photographingtime and the photographing location, which is input thereto from thephotographing location setting unit 60 via the main CPU 31.

—Color Information on the Photographic Subject—

Based upon the spectral distribution detected in correspondence to theindividual block areas, the scene analysis unit 35 detects colorinformation indicating the color of the primary photographic subject.For instance, let us assume that the processing unit 54 detects thespectral distribution indicated in FIG. 4B over an area ranging from ablock r1 to a block rn in the image plane divided into small blocks, asshown in FIG. 4A. Since this spectral distribution shows a great deal ofthe R component, the scene analysis unit 55 judges that the color of thesubject present over this area is red. In addition, since the blocksfrom which the R component is output at a high ratio form asubstantially circular shape, as indicated in FIG. 4A, the sceneanalysis unit 55 is able to estimate from the particulars of the subjectpresent over this area that the subject is a round, red object such as ared ball or an apple. If, on the other hand, the color of the subjectpresent over the blocks r1˜rn is judged to be skin color based upon thespectral distribution manifesting over this area, the scene analysisunit 55 is able to estimate that a person's face occupies the area.Furthermore, by using the information indicating the photographingdistance and the focal length, which is input from the main CPU 31, thescene analysis unit 55 is able to determine the size of the face andestimate the age of the photographic subject, e.g., whether thephotographic subject is a baby or an adult. If the subject is judged tobe a baby, the main CPU 31 may impose restrictions on light emission atan electronic flash unit (not shown).

—Extracting Feature of the Photographic Subject—

The scene analysis unit 55 extracts the feature of the subject bycomparing the spectral distribution over the entire area of thephotographic image, i.e., the light source information (colortemperature) with the spectral distribution detected in each block area.Namely, by deducing the inherent spectral reflectance of the subjectbased upon the spectral distribution manifesting in each block areaaffected by the light source, the scene analysis unit 55 identifies acolor inherent to the subject. The scene analysis unit 55 determines thecolor of each block area by referencing Table 1 indicating thecorrespondence among the R, G and B value ratios over the entire area ofthe photographic image, the color temperature and the coefficient, andTable 2 indicating the correspondence between R, G and B value ratios ineach block area and the color temperature, both stored at the database56. For instance, let us assume that the R, G and B value ratios overthe entire area of the photographic image are 2:5:10 and that the colortemperature has been judged to be 600°K. The scene analysis unit 55references Table 1 shown in FIG. 5A and selects a coefficient A1 incorrespondence to these values. Let us also assume that the ratios ofthe values obtained by multiplying the R, G and B values in a givenblock area by the coefficient A1 are 10:5:1. The scene analysis unit 55references Table 2 shown in FIG. 5B and determines the color of theblock area to be red in correspondence to these ratios. Moreover, if theshape of the spectral distribution curve over the entire area of thephotographic image indicated by the dotted line and the shape of thespectral distribution curve manifesting in the block area, indicated bythe solid line, substantially match (are similar to each other), asshown in FIG. 6, the scene analysis unit 55 judges the particular blockarea to be an achromatic area.

The photographing processing executed in the electronic camera describedabove is now explained in reference to the flowchart presented in FIG.7. The program in conformance to which the processing in FIG. 7 isexecuted is stored in a ROM (not shown) in the main CPU 31 and isstarted up in response to an ON signal input to the main CPU 31 from acamera power source.

In step S1 in FIG. 7, camera POWER ON processing is executed before theoperation proceeds to step S2. As a result, power is supplied to theindividual blocks (excluding the image-capturing element and itsperipheral circuits) from a power source circuit (not shown). In stepS2, the camera initializes itself by, for instance, selecting specificport settings and then the operation proceeds to step S3. In step S3,the default photographing mode and the initial settings for the displayand the image processing are selected before the operation proceeds tostep S4.

In step S4, a decision is made as to whether or not the single shot modehas been selected as the photographing mode. If it is decided that thesingle shot mode has been selected as the photographing mode, anaffirmative decision is made in step S4, and in this case, the operationproceeds to step S5 to execute photographing processing in the singleshot mode. If, on the other hand, the single shot mode has not beenselected as the photographing mode, a negative decision is made in stepS4 and the operation proceeds to step S6. In step S6, a decision is madeas to whether or not the continuous shooting mode has been selected asthe photographing mode. If it is decided that the continuous shootingmode has been selected as the photographing mode, an affirmativedecision is made in step S6 and the operation proceeds to step S7 toexecute photographing processing in the continuous shooting mode. If, onthe other hand, it is decided that the continuous shooting mode has notbeen selected as the photographing mode, a negative decision is made instep S6 and the operation proceeds to step S8. In step S8, a decision ismade as to whether or not the dynamic image mode has been selected asthe photographing mode. If it is decided that the dynamic image mode hasbeen selected as the photographing mode, an affirmative decision is madein step S8 and the operation proceeds to step S9 to execute processingin the dynamic image mode. If, on the other hand, it is decided that thedynamic image mode has not been selected as the photographing mode,i.e., if the through image display mode has been selected, a negativedecision is made in step S8 and the operation proceeds to step S10 toexecute processing in the through image display mode.

—Single Shot Mode—

In reference to FIG. 8, the photographing processing executed in thesingle shot mode in step S5 is explained. In the single shot mode, imageprocessing is executed on the photographic image based upon the sceneanalysis results.

In step S101, a decision is made as to whether or not the shutterrelease button has been pressed halfway down. If a halfway press signalhas been input from the halfway press switch 47, an affirmative decisionis made in step S101 to proceed to step S102, whereas if no halfwaypress signal has been input, a negative decision is made in step S101 torepeatedly execute the decision-making processing described above.

In step S102, the focal point detection device 49 detects the focalpoint adjustment state achieved via the lens 25 and the lens drivedevice 50 executes focal point adjustment based upon the focal pointdetection results. In step S103, a decision is made as to whether or notthe shutter release button has been pressed all the way down. Anaffirmative decision is made in step S103 if a full press signal isinput from the full press switch 48 to proceed to step S105, whereas anegative decision is made in step S103 if no full press signal has beeninput to proceed to step S104.

In step S105, a photographing sequence is started. More specifically,the mirror is made to start moving upward via a sequence device (notshown) and then the operation proceeds to step S106. In step S106, POWERON processing is executed to supply power to the photographicimage-capturing element 13 and its peripheral circuits (the AFE circuit34, the A/D conversion circuit 35, the timing generator 32 and thedriver 33) and the photographic image-capturing element 13 isinitialized, before the operation proceeds to step S107.

In step S107, the photographic image-capturing element 13 is engaged tostart an image-capturing operation. Namely, electrical charge storageand stored charge transfer are executed at the photographicimage-capturing element 13. In step S108, the sub CPU 53 executes ascene analysis on the image data (raw data) output from the photographicimage-capturing element 13. It is to be noted that the scene analysisprocessing is to be described in detail later in reference to theflowchart presented in FIG. 12.

In step S109, the mirror is made to start descending via the sequencedevice (not shown) before the operation proceeds to step S110. In stepS110, the image processing circuit 30 executes the image processing (theimage preprocessing and the image post processing) on the image havingbeen captured by the photographic image-capturing element 13 based uponthe results of the scene analysis having been executed in step S108.

In step S111, the image compression circuit 44 executes imagecompression processing on the digital image signals having undergone theimage postprocessing. In step S112, the image data resulting fromcompression processing are recorded into the recording medium 45, andthen the operation proceeds to step S113. In step S113, the displayimage generation circuit 42 generates display data by using the digitalimage signals having undergone the image preprocessing and aphotographic image corresponding to the display data is reproduced anddisplayed at the external monitor 43. The photographing operationsequence in the single shot mode then ends.

In step S104 to which the operation proceeds after making a negativedecision in step S103, a decision is made as to whether or not apredetermined length of time has elapsed since the start of the halfwaypress operation. An affirmative decision is made in step S104 if a statein which no halfway press signal is input from the halfway press switch47 has been sustained over the predetermined length of time, and in thiscase, the operation returns to step S101. If, on the other hand, ahalfway press signal has just been input from the halfway press switch47 or the state in which no halfway press signal is input has not beensustained over the predetermined length of time, a negative decision ismade in step S104 and the operation returns to step S103.

—Continuous Shooting Mode—

The photographing processing executed in the continuous shooting mode instep S7 in FIG. 7 is now explained in reference to FIG. 9. In thecontinuous shooting mode, the image processing is executed on thephotographic image and the photographing condition settings includingthe exposure value are selected for a second image or a subsequent imageto be photographed, based upon the scene analysis results.

The processing executed in step S201 (decision-making with regard towhether or not the shutter release button has been pressed halfway down)through step S208 (scene analysis) is similar to the processing executedin step S101 (decision-making with regard to whether or not the shutterrelease button has been pressed halfway down) through step S108 (sceneanalysis) in FIG. 8.

In step S209, the image processing circuit 30 executes the imageprocessing (image preprocessing and image post processing) for the imagecaptured at the photographic image-capturing element 13 based upon theresults of the scene analysis, and then the operation proceeds to stepS210. In step S210, the image compression circuit 44 executes the imagecompression processing on the digital image signals having undergone theimage postprocessing before the operation proceeds to step S211. In stepS211, the image data resulting from the compression processing arerecorded into the recording medium 45 and then the operation proceeds tostep S212.

In step S212, the display image generation circuit 42 generates displaydata by using the digital image signals having undergone the imagepreprocessing and a photographic image corresponding to the display datais reproduced and displayed at the external monitor 43. In step S213, adecision is made as to whether or not the continuous shooting speed isequal to or higher than a predetermined level. If the continuousshooting speed is judged to be equal to or higher than the predeterminedlevel, an affirmative decision is made in step S213 to proceed to stepS214, whereas if the continuous shooting speed is judged to be lowerthan the predetermined level, a negative decision is made in step S213to proceed to step S217.

In step S214, a decision is made as to whether or not the continuousshooting operation is to end. If it is decided that the continuousshooting operation is to continue, e.g., if the ON signal iscontinuously being output from the full press switch 48, a negativedecision is made in step S214 to proceed to step S216 in which thephotographing condition settings are selected based upon the results ofthe scene analysis having been obtained in step S208 before theoperation returns to step S206. If, on the other hand, it is decidedthat the continuous shooting operation is to end, e.g., if the ON signalis no longer being input from the full press switch 48, an affirmativedecision is made in step S214 to proceed to step S215 to lower themirror via the sequence device (not shown) and thus end the processingsequence in the continuous shooting mode.

In step S217, to which the operation proceeds after making a negativedecision in step S213, the mirror is made to start descending via thesequence device (not shown) as in step S215 and then the operationproceeds to step S218. In step S218, a decision is made as in step S214as to whether or not the continuous shooting operation is to end. If itis decided that the continuous shooting operation is to continue, anegative decision is made in step S218 and the operation returns to stepS205. If, on the other hand, the continuous shooting operation is toend, an affirmative decision is made in step S218 and the processingsequence in the continuous shooting mode ends.

—Dynamic Image Mode—

FIG. 10 shows the processing executed in the dynamic image mode in stepS9 in FIG. 7. In the dynamic image mode, too, the image processing isexecuted for the photographic image and also the photographing conditionsettings such as the exposure value for a subsequent image to bephotographed are selected, based upon the results of the scene analysis,as in the continuous shooting mode.

It is to be noted that the processing executed in step S301(decision-making with regard to whether or not the shutter releasebutton has been pressed halfway down) through step S312 (image display)is similar to the processing executed in step S201 (decision-making withregard to whether or not the shutter release button has been pressedhalfway down) through step S212 (image display) in the continuousshooting mode, as shown in FIG. 9. In step S313, a decision is made asto whether or not the dynamic image photographing operation is to end.If the dynamic image photographing operation is to continue, a negativedecision is made in step S313 to proceed to step S315 in which thephotographing condition settings are selected based upon the sceneanalysis results obtained through the processing executed in step S308as in step S216 in the continuous shooting mode shown in FIG. 9, andthen the operation returns to step S306. If, on the other hand, thedynamic image photographing operation is to end, an affirmative decisionis made in step S313 to proceed to step S314 in which the mirror is madeto descend via the sequence device (not shown) before ending theoperational sequence.

—Through Image Mode—

FIG. 11 shows the processing executed in the through image display modein step S10 in FIG. 7. When the through image display is brought up byholding the quick-return mirror 11 at the UP position indicated by thesolid line in FIG. 1 in the through image display mode, the imagedisplay processing is executed for the display image based upon theresults of the scene analysis and also the photographing conditionsettings such as the exposure value for a second or subsequent image tobe brought up on display are selected, based upon the scene analysisresults. When the through image display is brought up by driving thequick-return mirror 11 up/down in correspondence to each frame, theimage processing is executed for the display image based upon theresults of the scene analysis.

The processing executed in step S401 (decision-making with regard towhether or not the shutter release button has been pressed halfway down)through step S404 (decision-making with regard to the length of timeover which the shutter release button has been held halfway down) issimilar to the processing executed in step S301 (decision-making withregard to whether or not the shutter release button has been pressedhalfway down) through step S304 (decision-making with regard to thelength of time over which the shutter release button has been heldhalfway down) in the dynamic image mode as shown in FIG. 10. In stepS405 to which the operation proceeds after making an affirmativedecision in step S404, a decision is made as to whether or not todisplay a through image while holding the quick-return mirror 11 at theUP position indicated by the solid line in FIG. 1. If the display is tobe brought up by holding the quick-return mirror 11 at the UP position,an affirmative decision is made in step S405 and the operation proceedsto step S406. If, on the other hand, the display is to be brought up bydriving the quick-return mirror 11 up/down for each frame, a negativedecision is made in step S405 and the operation proceeds to step S415.

The processing executed from step S406 (mirror up) through step S410(image processing) is similar to the processing executed in step S305(mirror up) through step S309 (image processing) in the dynamic imagemode as shown in FIG. 10. In step S411, a through image is displayed atthe external monitor 43 via the display image generation circuit 42 andthen the operation proceeds to step S412. In step S412, a decision ismade as to whether or not to continue the through image display. If thethrough image display is to end, an affirmative decision is made in stepS412 and the operation proceeds to step S413 to lower the quick-returnmirror 11 and end the processing sequence. If the through image displayis to continue, a negative decision is made in step S412 to proceed tostep S414 in which the photographing condition settings are selectedbased upon the results of the scene analysis having been obtained instep S409 as in step S315 in the dynamic image mode in FIG. 10, beforethe operation returns to step S407.

The processing executed in step S415 (mirror up) through step S420(image processing) after making a negative decision in step S405 issimilar to the processing executed in step S105 (mirror up) through stepS110 (image processing) in the single shot mode as shown in FIG. 8. Instep S421, a through image is displayed at the external monitor 43 viathe display image generation circuit 42 as in step S411. In step S422, adecision is made as to whether or not to continue the through imagedisplay, as in step S412. If the through image display is to end, anaffirmative decision is made in step S422 and the processing sequenceends. If the through image display is to continue, a negative decisionis made in step S422 and the operation returns to step S415.

—Scene Analysis Processing—

The scene analysis processing executed in step S108 in FIG. 8, step S208in FIG. 9, step S308 in FIG. 10 and steps S409 and S418 in FIG. 11 isexplained in reference to the flowchart presented in FIG. 12. It is tobe noted that the program in conformance to which the processing shownin FIG. 12 proceeds is executed by the sub CPU 53.

In step S511, the processing unit 54 detects the spectral distributionmanifesting over the entire area of the photographic image and then theoperation proceeds to step S512. In step S512, the processing unit 54detects the spectral distribution manifesting over each block areabefore the operation proceeds to step S513. In step S513, the processingunit 54 calculates the absolute brightness value in correspondence toeach block area and then the operation proceeds to step S514.

In step S514, the scene analysis unit 55 detects the color temperatureof the photographic image, i.e., the light source information, basedupon the spectral distribution over the entire area of the photographicimage having been detected in step S511 by referencing the table storedin the database 56. In the following step S515, the scene analysis unit55 identifies the specific photographing locale based upon the absolutebrightness values having been calculated in step S513 and thephotographing information related to the photographing location and thephotographing time, and then the operation proceeds to step S516.

In step S516, the scene analysis unit 55 detects color informationrelated to the color of the photographic subject based upon the spectraldistributions in the individual block areas having been detected in stepS512, and then the operation proceeds to step S517. In step S517, thescene analysis unit 55 extracts feature of the subject based upon thespectral distribution over the entire area of the photographic imagehaving been detected in step S511 and the spectral distributionsmanifesting in the individual block areas having been detected in stepS512 by referencing the table stored in the database 56.

In the field indicated by reference numeral 151 in FIG. 24, eachphotographing mode that may be selected in the first embodiment and thecorresponding processing executed in the photographing mode is listed.

In the single shot mode, the scene analysis results are reflected in theimage processing executed on the photographic image. In the continuousshooting mode, the dynamic image mode and the through image displaymode, the image processing is executed on the photographic image or thedisplay image based upon the scene analysis results and also thephotographing condition settings such as the exposure value for asubsequent image are selected based upon the scene analysis results.

The following advantages are achieved in the electronic camera in thefirst embodiment described above.

(1) As the photographic image-capturing element 13 outputs digital imagesignals representing a plurality of color components, the sub CPU 53executes scene analysis for a photographic image by using a digitalimage signal output (raw data) with linearity. Thus, the processing canbe completed faster than scene analysis processing executed by firstconverting digital image signals to image data.(2) The sub CPU 53 executes scene analysis by calculating colorcontinuity manifesting over the entire area of the photographic imagebased upon a discrete spectral distribution of the plurality of colorcomponents represented in the digital image signals. Thus, the lightsource of the light illuminating the photographic image can bedetermined through scene analysis executed by using the raw data.(3) The sub CPU 53 executes scene analysis based upon continuitymanifesting in the spectral characteristics over the entire photographicimage and continuity manifesting in spectral characteristics in smallareas defined by dividing the entire photographic image. Thus, anachromatic area in the photographic image can be extracted through sceneanalysis executed by using the raw data.(4) The sub CPU 53 executes scene analysis based upon discrete spectralcharacteristics of the individual color components, R, G and B,manifesting over the entire photographic image and discrete spectralcharacteristics of the R, G and B color components manifesting in smallareas defined by dividing the entire photographic image. Thus,characteristics of the color in a small area can be extracted byascertaining the inherent spectral reflectance manifesting in the smallarea based upon the spectral characteristics of the small area affectedby the particular light source through scene analysis executed on theraw data.(5) The sub CPU 53 executes scene analysis by calculating an absolutebrightness value over the entire photographic image based upon thebrightness values calculated in correspondence to the individual colorcomponents, R, G and B, for the entire area of the photographic image.This makes it possible to estimate the photographing location, e.g., anindoors location or an outdoors location, based upon the absolutebrightness value.(6) The sub CPU 53 executes scene analysis by using the colortemperature and the absolute brightness value for the overallphotographic image. Thus, the photographing conditions, e.g., the imagehas been photographed indoors, illuminated with a fluorescent lamp or anincandescent lamp, can be estimated.(7) The main CPU 31 calculates the optimal photographing conditionsettings such as the optimal exposure value based upon the results ofthe scene analysis executed by using raw data output from thephotographic image-capturing element 13. This feature, which allows thescene analysis to be executed without having to convert digital imagesignals to image data and thus allows the processing to be completedmore quickly, is effective in, for instance, the continuous shootingmode in which the photographing condition settings must be determinedthrough arithmetic operation quickly.(8) Since the sub CPU 53 executes scene analysis by using the dataoutput from the photographic image-capturing element 13, the imageprocessing circuit 30 is able to reflect the scene analysis results inthe image processing that it executes on an image obtained through asingle shot photographing operation. In addition, the image processingcircuit 30 is able to reflect the scene analysis results in the imageprocessing that it executes on images obtained through a continuousshooting operation and a dynamic image photographing operation and on animage to be brought up in a through image display, and also, the mainCPU 31 is able to select the optimal photographing condition settingsfor subsequent images by using the analysis results.

Second Embodiment

FIG. 13 is a block diagram showing the circuit structure of theelectronic camera achieved in the second embodiment assuming theessential structure shown in FIG. 1, which executes scene analysis byusing image data (raw data) constituted with auxiliary image signalsoutput from the auxiliary image-capturing element 19. The followingexplanation focuses on differences from the circuit structure adopted inthe first embodiment shown in FIG. 2.

A timing generator (TG) 36 generates a timing signal in response to acommand output from the main CPU 31 and provides the timing signal to adriver 37, an AFE circuit 39 and an A/D conversion circuit 40. Thedriver 37 generates a drive signal to be used to engage the auxiliaryimaging element 19 in electrical charge storage and then in transfer ofthe stored electrical charges by using the timing signal and providesthe drive signal thus generated to the auxiliary image-capturing element19. The AFE circuit 39 executes analog processing (such as gain control)on photoelectric conversion signals (stored electrical charges) outputfrom the auxiliary image-capturing element 19. The A/D conversioncircuit 40 converts the imaging signals having undergone the analogprocessing to digital signals. The raw data constituted with thesedigital signals are output to the main CPU 31 which then executes sceneanalysis by using the raw data input thereto.

The main CPU 31 executes scene analysis based upon the raw dataoriginating from the auxiliary image-capturing element 19, which areinput thereto from the A/D conversion circuit 40, selects thephotographing condition settings based upon the scene analysis resultsin the single shot mode, the continuous shooting mode, the dynamic imagemode and the through image display mode, and outputs the scene analysisresults to the image processing circuit 30. The image processing circuit30 executes image processing on the digital image signals input theretofrom the A/D conversion circuit 35. It is to be noted that sceneanalysis is executed by adopting a method similar to that adopted in thesub CPU 53 in the first embodiment.

The photographing operation processing executed in the electronic cameraachieved in the second embodiment structured as described above is nowexplained. In the second embodiment, the photographing conditionsettings are selected based upon the scene analysis results when thesingle shot mode has been selected via the mode selector switch 52, andimage processing is executed for the photographic images or the displayimage, as well as selecting the photographing condition settings, basedupon the scene analysis results when the continuous shooting mode or thethrough image display mode has been selected via the mode selectorswitch 52. When the dynamic image mode has been selected, thephotographing condition settings are selected and image processing isexecuted for the photographic images based upon the scene analysisexecuted by obtaining the first photographic image. It is to be notedthat image processing may be executed based upon the scene analysisresults in the single shot mode as well. In such a case, the imageprocessing should be executed on image data output from the photographicimage-capturing element 13 based upon the results of the scene analysisexecuted by using image data output from the auxiliary image-capturingelement 19 before the quick-return mirror 11 rotates to the UP positionin FIG. 1.

—Single Shot Mode—

In reference to the flowchart presented in FIG. 14, the photographingoperation executed in the single shot mode is explained by focusing onthe processing, which differs from that shown in the flowchart presentedin FIG. 8.

In step S602 to which the operation proceeds after making an affirmativedecision with regard to a halfway press operation of the shutter releasebutton in step S601, POWER ON processing is executed to supply power tothe auxiliary image-capturing element 19 and its peripheral circuits(the AFE circuit 39, the A/D conversion circuit 40, the timing generator36 and the driver 37) and the auxiliary image-capturing element 19 isinitialized before the operation proceeds to step S603.

In step S604 to which the operation proceeds after executing focal pointdetection and adjustment in step S603 as in step S102 in FIG. 8, animaging operation at the auxiliary image-capturing element 19 starts.Namely, electrical charges are stored and the stored charges aretransferred at the auxiliary image-capturing element 19. In step S605,the main CPU 31 executes scene analysis on image data (raw data) outputfrom the auxiliary image-capturing element 19. It is to be noted thatsince the details of the scene analysis processing are similar to thosein the flowchart presented in FIG. 12, their explanation is omitted.

In step S606, the photographing condition settings are selected basedupon the results of the scene analysis having been executed in stepS605, and then the operation proceeds to step S607. The processingexecuted in step S607 (decision-making with regard to whether or not theshutter release button has been pressed all the way down) through stepS611 (electrical charge storage and transfer at the photographicimage-capturing element 13) is similar to the processing executed instep S103 (decision-making with regard to whether or not the shutterrelease button has been pressed all the way down) through step S107(electrical charge storage and transfer at the photographicimage-capturing element 13) in FIG. 8. In addition, the processingexecuted in step S612 (mirror down) through step S616 (image display) issimilar to the processing executed in step S109 (mirror down) throughstep S113 (image display) in FIG. 8. It is also to be noted that theimage processing is executed in step S613 by using the scene analysisresults obtained in step S605 immediately before the shutter releasebutton is pressed all the way down.

—Continuous Shooting Mode—

In reference to the flowchart presented in FIG. 15, the photographingoperation executed in the continuous shooting mode is explained. In thecontinuous shooting mode, the photographing condition settings areselected and the image processing for the photographic image is executedbased upon the scene analysis results.

The processing executed in step S701 (decision-making with regard towhether or not the shutter release button has been presses halfway down)through step S711 (electrical charge storage and transfer at thephotographic image-capturing element 13) in FIG. 15 is similar to theprocessing executed in step S601 (decision-making with regard to whetheror not the shutter release button has been pressed halfway down) throughstep S611 (electrical charge storage and transfer at the photographicimaging element 13) in the single shot mode as shown in FIG. 14. Inaddition, the processing executed in step S712 (image processing)through step S718 (mirror down) in FIG. 15 is similar to the processingexecuted in step S209 (image processing) through step S215 (mirror down)in FIG. 9. It is also to be noted that the image processing is executedin step S712 by using the scene analysis results obtained in step S705or the scene analysis results obtained in step S722.

As in steps S217 and S218 in FIG. 9, the quick-return mirror 11 islowered and then a decision is made as to whether or not the continuousshooting operation is to end in steps S719 and S720 in FIG. 15. If thecontinuous shooting operation is to continue, a negative decision ismade in step S720 and the operation proceeds to step S721. Theprocessing executed in step S721 (electrical charge storage and transferat the auxiliary image-capturing element 19) through step S723(photographing condition setting selection) is similar to the processingexecuted in step S704 (electrical charge storage and transfer at theauxiliary image-capturing element 19) through step S706 (photographingcondition setting selection).

—Dynamic Image Mode—

In reference to the flowchart presented in FIG. 16, the photographingoperation executed in the dynamic image mode is explained. In thedynamic image mode, the photographing condition settings are selectedand the image processing for the photographic image is executed basedupon the results of the scene analysis executed when the firstphotographic image is obtained.

The processing executed in step S801 (decision-making with regard towhether or not the shutter release button has been pressed halfway down)through step S815 (image display) in FIG. 16 is similar to theprocessing executed in step S701 (decision-making as to whether or notthe shutter release button has been pressed halfway down) through stepS715 (image display) in the continuous shooting mode as shown in FIG.15. It is to be noted that the image processing is executed in step S812by using the results of the scene analysis having been executed in stepS805. In addition, the processing executed in step S816 (decision-makingas to whether or not the dynamic image photographing operation is toend) through step S817 (mirror down) in FIG. 16 is similar to theprocessing executed in step S313 (decision-making as to whether or notthe dynamic image photographing operation is to end) through step S314(mirror down) in FIG. 10.

—Through Image Mode—

In reference to the flowchart presented in FIG. 17, the operationexecuted in the through image display mode is explained. In the throughimage display mode, the photographing condition settings are selectedand the image processing for the display image is executed based uponthe results of the scene analysis.

The processing executed in step S901 (decision-making as to whether ornot the shutter release button has been pressed halfway down) throughstep S908 (decision-making with regard to the length of time over whichthe shutter release button has been held halfway down) in FIG. 17 issimilar to the processing executed in step S801 (decision-making withregard to whether or not the shutter release button has been pressedhalfway down) through step S808 (decision-making with regard to thelength of time over which the shutter release button has been heldhalfway down) in the dynamic image mode as shown in FIG. 16.

In step S909, a decision is made as to whether or not to bring up thethrough image display by holding the quick-return mirror 11 at the UPposition indicated by the solid line in FIG. 1, as in step S405 in FIG.11. If the display is to be brought up by holding the quick-returnmirror 11 at the UP position, an affirmative decision is made in stepS909 and the operation proceeds to step S910. If, on the other hand, thedisplay is to be brought up by driving the quick-return mirror 11up/down for each frame, a negative decision is made in step S909 and theoperation proceeds to step S917.

The processing executed in step S910 (mirror up) through step S913(image processing) is similar to the processing executed in step S809(mirror up) through step S812 (image processing) in the dynamic imagemode as shown in FIG. 16. It is to be noted that the image processing isexecuted in step S913 by using the scene analysis results obtained instep S905. In step 5914, a through image is brought up on display at theexternal monitor 43 via the display image generation circuit 42, andthen the operation proceeds to step S915. In step S315, a decision ismade as to whether or not to exit the through image display mode. If thethrough image display mode is to continue, a negative decision is madein step S915 and the operation returns to step S911. If, on the otherhand, the through image display mode is to end, an affirmative decisionis made in step S915 and in this case, the operation proceeds to stepS916 to lower the quick-return mirror 11 and end the processingsequence.

The processing executed in step S917 (mirror up) through step S921(image processing) after making a negative decision in step S909 issimilar to the processing executed in step S609 (mirror up) through stepS613 (image processing) in the single shot mode as shown in FIG. 14. Itis to be noted that the image processing is executed in step S921 forthe first image by using the scene analysis results obtained in stepS905 and for any subsequent image by using the scene analysis resultsobtained in step S925. In step S922, a through image is brought up ondisplay at the external monitor 43 via the display image generationcircuit 42 as in step S913, and then the operation proceeds to stepS923.

In step S923, a decision is made as to whether or not to exit thethrough image display mode as in step S915. If the through image displaymode is to end, an affirmative decision is made in step S923 and theprocessing sequence ends. If, on the other hand, the through imagedisplay mode is to continue, a negative decision is made in step S923and the operation proceeds to step S924. The processing executed in stepS924 (electrical charge storage and transfer at the auxiliaryimage-capturing element 19) through step S926 (photographing conditionsetting selection) is similar to the processing executed in step S904(electrical charge storage and transfer at the auxiliary image-capturingelement 19) through step S906 (photographing condition settingselection).

In the field indicated by reference numeral 152 in FIG. 24, each of thephotographing modes that may be selected in the second embodiment andthe corresponding processing executed in the photographing mode islisted.

In the single shot mode, the main CPU 31 selects the photographingcondition settings based upon the scene analysis results. In addition,the image processing circuit 30 executes image processing for aphotographic image based upon the results of the scene analysis havingbeen executed prior to raising the mirror. In the continuous shootingmode or the through image display mode, the main CPU 31 selects thephotographing condition settings based upon the scene analysis resultsand the image processing circuit 30 executes the image processing forthe photographic image or the display image based upon the results ofthe scene analysis. In the dynamic image mode, the main CPU 31 selectsthe photographing condition settings and the image processing circuit 30executes the image processing based upon the results of the sceneanalysis executed when the first image is obtained.

In addition to the advantages (2) through (6) achieved in the firstembodiment, the electronic camera in the second embodiment describedabove provides the following advantages.

(1) As digital image signals representing a plurality of colorcomponents output from the auxiliary image-capturing element 19, themain CPU 31 executes scene analysis for a photographic image by using adigital image signal output (raw data) with linearity. Thus, theprocessing can be completed faster than scene analysis processingexecuted by first converting digital image signals to image data.(2) The main CPU 31 determines through arithmetic operation the optimalphotographing condition settings such as the optimal exposure valuebased upon the results of the scene analysis executed by using raw dataoutput from the auxiliary image-capturing element 19. Since this featureallows the scene analysis processing to be completed without having toconvert digital image signals to image data, the overall processing timeis reduced. In addition, the results of the scene analysis executed byusing the data output from the auxiliary image-capturing element 19 canbe utilized when determining through arithmetic operation thephotographing condition settings for the first image in the single shotmode, the continuous shooting mode, the dynamic image mode and thethrough image display mode.(3) Based upon the results of the scene analysis executed by using rawdata output from the auxiliary image-capturing element 19, the imageprocessing circuit 30 executes image processing for data output from thephotographic image-capturing element 13. This feature, which allows thescene analysis to be executed without having to first convert digitalimage signals to image data and thus allows the processing to becompleted more quickly, is effective in, for instance, the continuousshooting mode in which the photographing condition settings must bedetermined quickly through arithmetic operation.(4) Since the main CPU 31 executes the scene analysis based upon rawdata provided from the auxiliary image-capturing element 19 equippedwith a smaller number of pixels than the photographic image-capturingelement 13, the processing can be completed more quickly.

Third Embodiment

FIG. 18 is a block diagram showing the circuit structure adopted in theelectronic camera achieved in the third embodiment assuming theessential structure shown in FIG. 1, which executes scene analysis byusing image data (raw data) output from the photographic image-capturingelement 13 and the auxiliary image-capturing element 19. The electroniccamera achieved in the third embodiment includes a sub CPU 53 as doesthe electronic camera achieved in the first embodiment and the sub CPU53 executes scene analysis by using image data (raw data) constitutedwith photographic image signals output from the photographicimage-capturing element 13. In addition, the main CPU 31 in theelectronic camera executes scene analysis by using image data (raw data)constituted with auxiliary image signals output from the auxiliaryimage-capturing element 19, as in the second embodiment.

The operations executed in the electronic camera in the third embodimentstructured as described above in the single shot mode, the continuousshooting mode, the dynamic image mode and the through image display modeare respectively shown in the flowchart presented in FIG. 19, theflowchart presented in FIG. 20, the flowchart presented in FIG. 21 andthe flowchart presented in FIG. 22.

The operation executed in the single shot mode as shown in the flowchartpresented in FIG. 19 is a combination of the operations executed in thesingle shot mode, as shown in the flowchart presented in FIGS. 8 and 14.Namely, in the third embodiment, the main CPU 31 executes scene analysisbased upon image data provided from the auxiliary image-capturingelement 19 in step S1005 and then selects the photographing conditionsettings based upon the scene analysis results in the single shot mode.In addition, the main CPU 31 engages the sub CPU 53 to execute sceneanalysis based upon image data provided from the photographicimage-capturing element 13 in step S1012. Then, based upon the resultsof this scene analysis, the image processing circuit 30 executes imageprocessing on the photographic image.

The operation executed in the continuous shooting mode as shown in theflowchart presented in FIG. 20 is a combination of the operationsexecuted in the continuous shooting mode, as shown in the flowchartpresented in FIGS. 9 and 15. Namely, in the third embodiment, the mainCPU 31 executes scene analysis based upon image data provided from theauxiliary image-capturing element 19 in step S1105 and then selects thephotographing condition settings based upon the scene analysis resultsin the continuous shooting mode. In addition, the main CPU 31 engagesthe sub CPU 53 to execute scene analysis based upon image data providedfrom the photographic image-capturing element 13 in step S1112. Then,based upon the results of this scene analysis, the image processingcircuit 30 executes image processing on the photographic image. If thecontinuous shooting speed is set equal to or higher than a predeterminedlevel, the main CPU 31 selects the photographing condition settings fora second or subsequent photographic image and the image processingcircuit 30 executes the image processing for the second or subsequentimage by using the results of the scene analysis having been executed instep S1112. If, on the other hand, the continuous shooting speed is setto a level lower than the predetermined level, the main CPU 31 selectsthe photographing condition settings for the second or subsequentphotographic image by using the results of the scene analysis executedin step S1124 and the image processing circuit 30 executes the imageprocessing for the second or subsequent photographic image by using theresults of the scene analysis having been executed in step S1112.

The operation executed in the dynamic image mode as shown in theflowchart presented in FIG. 21 is a combination of the operationsexecuted in the dynamic image mode, as shown in the flowcharts presentedin FIGS. 10 and 16. Namely, in the third embodiment, the main CPU 31executes scene analysis based upon image data provided from theauxiliary image-capturing element 19 in step S1205 and then selects thephotographing condition settings for the first photographic image basedupon the scene analysis results in the dynamic image mode. In addition,the main CPU 31 engages the sub CPU 53 to execute scene analysis basedupon image data provided from the photographic image-capturing element13 in step S1212. Then, based upon the results of this scene analysis,the image processing circuit 30 executes image processing on thephotographic image and the main CPU 31 selects the photographiccondition settings for the second or subsequent photographic image.

The operation executed in the through image display mode as shown in theflowchart presented in FIG. 22 is a combination of the operationsexecuted in the through image display mode, as shown in a flowchartpresented in FIGS. 11 and 17. Namely, in the through image display modein the third embodiment, scene analysis is executed by the sub CPU 53and the main CPU 31 respectively based upon image data provided from thephotographic image-capturing element 13 and image data provided by theauxiliary image-capturing element 19. Then, the main CPU 31 selects thephotographing condition settings and the image processing circuit 30executes the image processing for the display image by using the sceneanalysis results. It is to be noted that the specific image data to beused for the scene analysis, i.e., either the image data output from thephotographic image-capturing element 13 or the image data output fromthe auxiliary image-capturing element 19, are selected in accordance towhether the through image display is brought up by holding thequick-return mirror 11 at the UP position or by driving the quick-returnmirror 11 up/down for each frame,

The advantages of the first and second embodiment are also achieved inthe electronic camera in the third embodiment.

The embodiments described above allow for the following variations.

(1) The spectral sensitivity characteristics of the photographicimage-capturing element 13 and the spectral sensitivity characteristicsof the auxiliary image-capturing element 19 may be different from eachother. In such a case, a smaller spectral sensitivity width may be setin correspondence to the R, G and B colors at the auxiliaryimage-capturing element 19 compared to the spectral sensitivity width ofthe R, G and B colors at the photographic image-capturing element 13, asshown in FIG. 23A. Alternatively, the spectral sensitivity peaks of theR, G and B colors at the auxiliary image-capturing element 19 may beoffset relative to the spectral sensitivity peaks of the R, G and Bcolors at the photographic image-capturing element 13, as shown in FIG.23B. By adjusting the spectral sensitivity characteristics as describedabove, it can be ensured that any color information that cannot bedetected via the photographic image-capturing element 13 can be capturedvia the auxiliary image-capturing element 19, making it possible tojudge the color with a high level of reliability.(2) In the explanation given above in reference to the embodiments, thephotographing operation in the continuous shooting mode is executedeither by holding the quick-return mirror 11 at the UP positionindicated by the solid line in FIG. 1 or by driving the quick-returnmirror 11 up/down for each photographic frame in accordance with thecontinuous shooting speed setting having been selected. Alternatively,the quick-return mirror 11 is either held or driven in response to asetting operation performed by the photographer as in the through imagedisplay mode.(3) In the through image display mode in the third embodiment, thespecific image data to be used for the scene analysis, i.e., either theimage data output from the photographic image-capturing element 13 orthe image data output from the auxiliary image-capturing element 19, aredetermined in accordance to whether the through image photographingoperation is executed by holding the quick-return mirror 11 at the UPposition or by driving the quick-return mirror up/down for eachphotographic frame. In stead, either the image data provided by thephotographic image-capturing element 13 or the image data provided bythe auxiliary image-capturing element 19 may be selected to be used inthe scene analysis in response to a setting operation performed by thephotographer and the quick-return mirror 11 may be held or driven basedupon the selection results.

The above described embodiments are examples, and various modificationscan be made without departing from the spirit and scope of theinvention.

1. An imaging apparatus, comprising: an image-capturing element that outputs image signals with linearity representing a plurality of color components by capturing a subject image passing through a photographic lens; and an analyzing device that executes scene analysis of a photographic image by using the image signals with linearity, wherein: the analyzing device extracts an achromatic area within an entire area of the photographic image based upon continuity of first spectral characteristics and continuity of second spectral characteristics, the first spectral characteristics manifesting over the entire area and the second spectral characteristics manifesting in small areas defined by dividing the entire area, and the analyzing device compares a first curve representing the first spectral characteristics manifesting over the entire area with a second curve representing the second spectral characteristics manifesting in the small area, and extracts the small area as the achromatic area if the first curve assumes a shape substantially matching a shape of the second curve.
 2. An imaging apparatus according to claim 1, wherein: the analyzing device executes the scene analysis by using a discrete spectral distribution of the plurality of color components represented in the image signals.
 3. An imaging apparatus according to claim 1, wherein: the analyzing device executes the scene analysis so as to detect a light source by calculating color continuity manifesting over the entire area based upon discrete spectral characteristics of the plurality of color components represented in the image signals.
 4. An imaging apparatus according to claim 2, wherein: the analyzing device executes the scene analysis so as to extract a feature of the photographic image based upon discrete spectral characteristics of the individual color components manifesting over the entire area and discrete spectral characteristics of the individual color components manifesting in the small areas.
 5. An imaging apparatus according to claim 1, wherein: the analyzing device executes the scene analysis so as to estimate a photographing location based upon an absolute value, the analyzing device calculating the absolute brightness value for the entire area based upon brightness values corresponding to the individual color components detected over the entire area.
 6. An imaging apparatus according to claim 5, wherein: the analyzing device executes the scene analysis so as to estimate a photographic condition based upon a color temperature and the absolute brightness value, the analyzing device calculating a color temperature for the entire are area.
 7. An imaging apparatus according to claim 1, further comprising: an arithmetic operation circuit that determines photographing condition settings through arithmetic operation based upon results of the scene analysis executed by the analyzing device, wherein: the image-capturing element executes a photographing operation at the photographing condition settings determined by the arithmetic operation circuit.
 8. An imaging apparatus according to claim 1, further comprising: an image processing circuit that executes image processing on the image signals based upon results of the scene analysis executed by the analyzing device.
 9. An imaging apparatus according to claim 1, wherein: the analyzing device executes the scene analysis upon the first spectral characteristics manifesting over the entire area the second spectral characteristics manifesting in the small areas and an absolute brightness value calculated in correspondence to each of the small areas.
 10. An imaging apparatus according to claim 4, wherein: the analyzing apparatus extracts the feature by identifying a color inherent to a subject.
 11. An imaging apparatus according to claim 7, further comprising: a selection unit that selects a specific mode among photographing modes including a single shot mode, a continuous shooting mode, a dynamic image mode and a through image mode, wherein: the arithmetic operation circuit determines the photographing condition settings through arithmetic operation based upon the results of the scene analysis and results of mode selection made by the selection unit.
 12. An imaging apparatus according to claim 8, further comprising: a selection unit that selects a specific mode among photographing modes including a single shot mode, a continuous shooting mode, a dynamic image mode and a through image mode, wherein: the image processing circuit executes the image processing based upon the results of the scene analysis and results of mode selection made by the selection unit.
 13. An imaging apparatus according to claim 1, the image signal with linearity is RAW data. 